The issue is with whitespace. You actually don't have any margins on your dividers or your boxes. Set either one to have margin left and right.
.vert {
margin-left: 5px;
margin-right: 5px;
}
Also, inline-block elements will show whitespace before and after them. You could set the div's back to display as block and float them left, along with the dividers. You will have to change the vert style to be margin-top instead of margin-bottom though.